src/vnet/config.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2015 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 /*
  * config.c: feature configuration
  *
  * Copyright (c) 2008 Eliot Dresselhaus
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sublicense, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * The above copyright notice and this permission notice shall be
  * included in all copies or substantial portions of the Software.
  *
  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */

 #include <vnet/vnet.h>

 static vnet_config_feature_t *
 duplicate_feature_vector (vnet_config_feature_t * feature_vector)
 {
   vnet_config_feature_t *result, *f;

   result = vec_dup (feature_vector);
   vec_foreach (f, result) f->feature_config = vec_dup (f->feature_config);

   return result;
 }

 static void
 free_feature_vector (vnet_config_feature_t * feature_vector)
 {
   vnet_config_feature_t *f;

   vec_foreach (f, feature_vector) vnet_config_feature_free (f);
   vec_free (feature_vector);
 }

 static u32
 add_next (vlib_main_t * vm,
 	  vnet_config_main_t * cm, u32 last_node_index, u32 this_node_index)
 {
   u32 i, ni = ~0;

   if (last_node_index != ~0)
     return vlib_node_add_next (vm, last_node_index, this_node_index);

   for (i = 0; i < vec_len (cm->start_node_indices); i++)
     {
       u32 tmp;
       tmp =
 	vlib_node_add_next (vm, cm->start_node_indices[i], this_node_index);
       if (ni == ~0)
 	ni = tmp;
       /* Start nodes to first must agree on next indices. */
       ASSERT (ni == tmp);
     }

   return ni;
 }

 static vnet_config_t *
 find_config_with_features (vlib_main_t * vm,
 			   vnet_config_main_t * cm,
 			   vnet_config_feature_t * feature_vector)
 {
   u32 last_node_index = ~0;
   vnet_config_feature_t *f;
   u32 *config_string;
   uword *p;
   vnet_config_t *c;

   config_string = cm->config_string_temp;
   cm->config_string_temp = 0;
   if (config_string)
     _vec_len (config_string) = 0;

   vec_foreach (f, feature_vector)
   {
     /* Connect node graph. */
     f->next_index = add_next (vm, cm, last_node_index, f->node_index);
     last_node_index = f->node_index;

     /* Store next index in config string. */
     vec_add1 (config_string, f->next_index);

     /* Store feature config. */
     vec_add (config_string, f->feature_config, vec_len (f->feature_config));
   }

   /* Terminate config string with next for end node. */
   if (last_node_index == ~0 || last_node_index != cm->end_node_index)
     {
       u32 next_index = add_next (vm, cm, last_node_index, cm->end_node_index);
       vec_add1 (config_string, next_index);
     }

   /* See if config string is unique. */
   p = hash_get_mem (cm->config_string_hash, config_string);
   if (p)
     {
       /* Not unique.  Share existing config. */
       cm->config_string_temp = config_string;	/* we'll use it again later. */
       free_feature_vector (feature_vector);
       c = pool_elt_at_index (cm->config_pool, p[0]);
     }
   else
     {
       u32 *d;

       pool_get (cm->config_pool, c);
       c->index = c - cm->config_pool;
       c->features = feature_vector;
       c->config_string_vector = config_string;

       /* Allocate copy of config string in heap.
          VLIB buffers will maintain pointers to heap as they read out
          configuration data. */
       c->config_string_heap_index
 	= heap_alloc (cm->config_string_heap, vec_len (config_string) + 1,
 		      c->config_string_heap_handle);

       /* First element in heap points back to pool index. */
       d =
 	vec_elt_at_index (cm->config_string_heap,
 			  c->config_string_heap_index);
       d[0] = c->index;
       clib_memcpy (d + 1, config_string, vec_bytes (config_string));
       hash_set_mem (cm->config_string_hash, config_string, c->index);

       c->reference_count = 0;	/* will be incremented by caller. */
     }

   return c;
 }

 void
 vnet_config_init (vlib_main_t * vm,
 		  vnet_config_main_t * cm,
 		  char *start_node_names[],
 		  int n_start_node_names,
 		  char *feature_node_names[], int n_feature_node_names)
 {
   vlib_node_t *n;
   u32 i;

   clib_memset (cm, 0, sizeof (cm[0]));

   cm->config_string_hash =
     hash_create_vec (0,
 		     STRUCT_SIZE_OF (vnet_config_t, config_string_vector[0]),
 		     sizeof (uword));

   ASSERT (n_feature_node_names >= 1);

   vec_resize (cm->start_node_indices, n_start_node_names);
   for (i = 0; i < n_start_node_names; i++)
     {
       n = vlib_get_node_by_name (vm, (u8 *) start_node_names[i]);
       /* Given node name must exist. */
       ASSERT (n != 0);
       cm->start_node_indices[i] = n->index;
     }

   vec_resize (cm->node_index_by_feature_index, n_feature_node_names);
   for (i = 0; i < n_feature_node_names; i++)
     {
       if (!feature_node_names[i])
 	cm->node_index_by_feature_index[i] = ~0;
       else
 	{
 	  n = vlib_get_node_by_name (vm, (u8 *) feature_node_names[i]);
 	  /* Given node may exist in plug-in library which is not present */
 	  if (n)
 	    {
 	      if (i + 1 == n_feature_node_names)
 		cm->end_node_index = n->index;
 	      cm->node_index_by_feature_index[i] = n->index;
 	    }
 	  else
 	    cm->node_index_by_feature_index[i] = ~0;
 	}
     }
 }

 static void
 remove_reference (vnet_config_main_t * cm, vnet_config_t * c)
 {
   ASSERT (c->reference_count > 0);
   c->reference_count -= 1;
   if (c->reference_count == 0)
     {
       hash_unset (cm->config_string_hash, c->config_string_vector);
       vnet_config_free (cm, c);
       pool_put (cm->config_pool, c);
     }
 }

 static int
 feature_cmp (void *a1, void *a2)
 {
   vnet_config_feature_t *f1 = a1;
   vnet_config_feature_t *f2 = a2;

   return (int) f1->feature_index - f2->feature_index;
 }

 always_inline u32 *
 vnet_get_config_heap (vnet_config_main_t * cm, u32 ci)
 {
   return heap_elt_at_index (cm->config_string_heap, ci);
 }

 u32
 vnet_config_modify_end_node (vlib_main_t * vm,
 			     vnet_config_main_t * cm,
 			     u32 config_string_heap_index, u32 end_node_index)
 {
   vnet_config_feature_t *new_features;
   vnet_config_t *old, *new;

   if (end_node_index == ~0)	// feature node does not exist
     return ~0;

   if (config_string_heap_index == ~0)
     {
       old = 0;
       new_features = 0;
     }
   else
     {
       u32 *p = vnet_get_config_heap (cm, config_string_heap_index);
       old = pool_elt_at_index (cm->config_pool, p[-1]);
       new_features = old->features;
       if (new_features)
 	new_features = duplicate_feature_vector (new_features);
     }

   if (vec_len (new_features))
     {
       /* is the last feature the cuurent end node */
       u32 last = vec_len (new_features) - 1;
       if (new_features[last].node_index == cm->end_node_index)
 	{
 	  vec_free (new_features->feature_config);
 	  _vec_len (new_features) = last;
 	}
     }

   if (old)
     remove_reference (cm, old);

   cm->end_node_index = end_node_index;

   new = find_config_with_features (vm, cm, new_features);
   new->reference_count += 1;

   /*
    * User gets pointer to config string first element
    * (which defines the pool index
    * this config string comes from).
    */
   vec_validate (cm->config_pool_index_by_user_index,
 		new->config_string_heap_index + 1);
   cm->config_pool_index_by_user_index[new->config_string_heap_index + 1]
     = new - cm->config_pool;
   return new->config_string_heap_index + 1;
 }

 u32
 vnet_config_add_feature (vlib_main_t * vm,
 			 vnet_config_main_t * cm,
 			 u32 config_string_heap_index,
 			 u32 feature_index,
 			 void *feature_config, u32 n_feature_config_bytes)
 {
   vnet_config_t *old, *new;
   vnet_config_feature_t *new_features, *f;
   u32 n_feature_config_u32s;
   u32 node_index = vec_elt (cm->node_index_by_feature_index, feature_index);

   if (node_index == ~0)		// feature node does not exist
     return ~0;

   if (config_string_heap_index == ~0)
     {
       old = 0;
       new_features = 0;
     }
   else
     {
       u32 *p = vnet_get_config_heap (cm, config_string_heap_index);
       old = pool_elt_at_index (cm->config_pool, p[-1]);
       new_features = old->features;
       if (new_features)
 	new_features = duplicate_feature_vector (new_features);
     }

   vec_add2 (new_features, f, 1);
   f->feature_index = feature_index;
   f->node_index = node_index;

   n_feature_config_u32s =
     round_pow2 (n_feature_config_bytes,
 		sizeof (f->feature_config[0])) /
     sizeof (f->feature_config[0]);
   vec_add (f->feature_config, feature_config, n_feature_config_u32s);

   /* Sort (prioritize) features. */
   if (vec_len (new_features) > 1)
     vec_sort_with_function (new_features, feature_cmp);

   if (old)
     remove_reference (cm, old);

   new = find_config_with_features (vm, cm, new_features);
   new->reference_count += 1;

   /*
    * User gets pointer to config string first element
    * (which defines the pool index
    * this config string comes from).
    */
   vec_validate (cm->config_pool_index_by_user_index,
 		new->config_string_heap_index + 1);
   cm->config_pool_index_by_user_index[new->config_string_heap_index + 1]
     = new - cm->config_pool;
   return new->config_string_heap_index + 1;
 }

 u32
 vnet_config_del_feature (vlib_main_t * vm,
 			 vnet_config_main_t * cm,
 			 u32 config_string_heap_index,
 			 u32 feature_index,
 			 void *feature_config, u32 n_feature_config_bytes)
 {
   vnet_config_t *old, *new;
   vnet_config_feature_t *new_features, *f;
   u32 n_feature_config_u32s;

   {
     u32 *p = vnet_get_config_heap (cm, config_string_heap_index);

     old = pool_elt_at_index (cm->config_pool, p[-1]);
   }

   n_feature_config_u32s =
     round_pow2 (n_feature_config_bytes,
 		sizeof (f->feature_config[0])) /
     sizeof (f->feature_config[0]);

   /* Find feature with same index and opaque data. */
   vec_foreach (f, old->features)
   {
     if (f->feature_index == feature_index
 	&& vec_len (f->feature_config) == n_feature_config_u32s
 	&& (n_feature_config_u32s == 0
 	    || !memcmp (f->feature_config, feature_config,
 			n_feature_config_bytes)))
       break;
   }

   /* Feature not found. */
   if (f >= vec_end (old->features))
     return ~0;

   new_features = duplicate_feature_vector (old->features);
   f = new_features + (f - old->features);
   vnet_config_feature_free (f);
   vec_delete (new_features, 1, f - new_features);

   /* must remove old from config_pool now as it may be expanded and change
      memory location if the following function find_config_with_features()
      adds a new config because none of existing config's has matching features
      and so can be reused */
   remove_reference (cm, old);
   new = find_config_with_features (vm, cm, new_features);
   new->reference_count += 1;

   vec_validate (cm->config_pool_index_by_user_index,
 		new->config_string_heap_index + 1);
   cm->config_pool_index_by_user_index[new->config_string_heap_index + 1]
     = new - cm->config_pool;
   return new->config_string_heap_index + 1;
 }

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* Copyright (c) 2015 Cisco and/or its affiliates.
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at:
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	/*
	* config.c: feature configuration
	*
	* Copyright (c) 2008 Eliot Dresselhaus
	*
	* Permission is hereby granted, free of charge, to any person obtaining
	* a copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sublicense, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:
	*
	* The above copyright notice and this permission notice shall be
	* included in all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
	* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
	* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
	* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	*/

	#include <vnet/vnet.h>

	static vnet_config_feature_t *
	duplicate_feature_vector (vnet_config_feature_t * feature_vector)
	{
	vnet_config_feature_t result, f;

	result = vec_dup (feature_vector);
	vec_foreach (f, result) f->feature_config = vec_dup (f->feature_config);

	return result;
	}

	static void
	free_feature_vector (vnet_config_feature_t * feature_vector)
	{
	vnet_config_feature_t *f;

	vec_foreach (f, feature_vector) vnet_config_feature_free (f);
	vec_free (feature_vector);
	}

	static u32
	add_next (vlib_main_t * vm,
	vnet_config_main_t * cm, u32 last_node_index, u32 this_node_index)
	{
	u32 i, ni = ~0;

	if (last_node_index != ~0)
	return vlib_node_add_next (vm, last_node_index, this_node_index);

	for (i = 0; i < vec_len (cm->start_node_indices); i++)
	{
	u32 tmp;
	tmp =
	vlib_node_add_next (vm, cm->start_node_indices[i], this_node_index);
	if (ni == ~0)
	ni = tmp;
	/* Start nodes to first must agree on next indices. */
	ASSERT (ni == tmp);
	}

	return ni;
	}

	static vnet_config_t *
	find_config_with_features (vlib_main_t * vm,
	vnet_config_main_t * cm,
	vnet_config_feature_t * feature_vector)
	{
	u32 last_node_index = ~0;
	vnet_config_feature_t *f;
	u32 *config_string;
	uword *p;
	vnet_config_t *c;

	config_string = cm->config_string_temp;
	cm->config_string_temp = 0;
	if (config_string)
	_vec_len (config_string) = 0;

	vec_foreach (f, feature_vector)
	{
	/* Connect node graph. */
	f->next_index = add_next (vm, cm, last_node_index, f->node_index);
	last_node_index = f->node_index;

	/* Store next index in config string. */
	vec_add1 (config_string, f->next_index);

	/* Store feature config. */
	vec_add (config_string, f->feature_config, vec_len (f->feature_config));
	}

	/* Terminate config string with next for end node. */
	if (last_node_index == ~0 \|\| last_node_index != cm->end_node_index)
	{
	u32 next_index = add_next (vm, cm, last_node_index, cm->end_node_index);
	vec_add1 (config_string, next_index);
	}

	/* See if config string is unique. */
	p = hash_get_mem (cm->config_string_hash, config_string);
	if (p)
	{
	/* Not unique. Share existing config. */
	cm->config_string_temp = config_string; /* we'll use it again later. */
	free_feature_vector (feature_vector);
	c = pool_elt_at_index (cm->config_pool, p[0]);
	}
	else
	{
	u32 *d;

	pool_get (cm->config_pool, c);
	c->index = c - cm->config_pool;
	c->features = feature_vector;
	c->config_string_vector = config_string;

	/* Allocate copy of config string in heap.
	VLIB buffers will maintain pointers to heap as they read out
	configuration data. */
	c->config_string_heap_index
	= heap_alloc (cm->config_string_heap, vec_len (config_string) + 1,
	c->config_string_heap_handle);

	/* First element in heap points back to pool index. */
	d =
	vec_elt_at_index (cm->config_string_heap,
	c->config_string_heap_index);
	d[0] = c->index;
	clib_memcpy (d + 1, config_string, vec_bytes (config_string));
	hash_set_mem (cm->config_string_hash, config_string, c->index);

	c->reference_count = 0; /* will be incremented by caller. */
	}

	return c;
	}

	void
	vnet_config_init (vlib_main_t * vm,
	vnet_config_main_t * cm,
	char *start_node_names[],
	int n_start_node_names,
	char *feature_node_names[], int n_feature_node_names)
	{
	vlib_node_t *n;
	u32 i;

	clib_memset (cm, 0, sizeof (cm[0]));

	cm->config_string_hash =
	hash_create_vec (0,
	STRUCT_SIZE_OF (vnet_config_t, config_string_vector[0]),
	sizeof (uword));

	ASSERT (n_feature_node_names >= 1);

	vec_resize (cm->start_node_indices, n_start_node_names);
	for (i = 0; i < n_start_node_names; i++)
	{
	n = vlib_get_node_by_name (vm, (u8 *) start_node_names[i]);
	/* Given node name must exist. */
	ASSERT (n != 0);
	cm->start_node_indices[i] = n->index;
	}

	vec_resize (cm->node_index_by_feature_index, n_feature_node_names);
	for (i = 0; i < n_feature_node_names; i++)
	{
	if (!feature_node_names[i])
	cm->node_index_by_feature_index[i] = ~0;
	else
	{
	n = vlib_get_node_by_name (vm, (u8 *) feature_node_names[i]);
	/* Given node may exist in plug-in library which is not present */
	if (n)
	{
	if (i + 1 == n_feature_node_names)
	cm->end_node_index = n->index;
	cm->node_index_by_feature_index[i] = n->index;
	}
	else
	cm->node_index_by_feature_index[i] = ~0;
	}
	}
	}

	static void
	remove_reference (vnet_config_main_t * cm, vnet_config_t * c)
	{
	ASSERT (c->reference_count > 0);
	c->reference_count -= 1;
	if (c->reference_count == 0)
	{
	hash_unset (cm->config_string_hash, c->config_string_vector);
	vnet_config_free (cm, c);
	pool_put (cm->config_pool, c);
	}
	}

	static int
	feature_cmp (void a1, void a2)
	{
	vnet_config_feature_t *f1 = a1;
	vnet_config_feature_t *f2 = a2;

	return (int) f1->feature_index - f2->feature_index;
	}

	always_inline u32 *
	vnet_get_config_heap (vnet_config_main_t * cm, u32 ci)
	{
	return heap_elt_at_index (cm->config_string_heap, ci);
	}

	u32
	vnet_config_modify_end_node (vlib_main_t * vm,
	vnet_config_main_t * cm,
	u32 config_string_heap_index, u32 end_node_index)
	{
	vnet_config_feature_t *new_features;
	vnet_config_t old, new;

	if (end_node_index == ~0) // feature node does not exist
	return ~0;

	if (config_string_heap_index == ~0)
	{
	old = 0;
	new_features = 0;
	}
	else
	{
	u32 *p = vnet_get_config_heap (cm, config_string_heap_index);
	old = pool_elt_at_index (cm->config_pool, p[-1]);
	new_features = old->features;
	if (new_features)
	new_features = duplicate_feature_vector (new_features);
	}

	if (vec_len (new_features))
	{
	/* is the last feature the cuurent end node */
	u32 last = vec_len (new_features) - 1;
	if (new_features[last].node_index == cm->end_node_index)
	{
	vec_free (new_features->feature_config);
	_vec_len (new_features) = last;
	}
	}

	if (old)
	remove_reference (cm, old);

	cm->end_node_index = end_node_index;

	new = find_config_with_features (vm, cm, new_features);
	new->reference_count += 1;

	/*
	* User gets pointer to config string first element
	* (which defines the pool index
	* this config string comes from).
	*/
	vec_validate (cm->config_pool_index_by_user_index,
	new->config_string_heap_index + 1);
	cm->config_pool_index_by_user_index[new->config_string_heap_index + 1]
	= new - cm->config_pool;
	return new->config_string_heap_index + 1;
	}

	u32
	vnet_config_add_feature (vlib_main_t * vm,
	vnet_config_main_t * cm,
	u32 config_string_heap_index,
	u32 feature_index,
	void *feature_config, u32 n_feature_config_bytes)
	{
	vnet_config_t old, new;
	vnet_config_feature_t new_features, f;
	u32 n_feature_config_u32s;
	u32 node_index = vec_elt (cm->node_index_by_feature_index, feature_index);

	if (node_index == ~0) // feature node does not exist
	return ~0;

	if (config_string_heap_index == ~0)
	{
	old = 0;
	new_features = 0;
	}
	else
	{
	u32 *p = vnet_get_config_heap (cm, config_string_heap_index);
	old = pool_elt_at_index (cm->config_pool, p[-1]);
	new_features = old->features;
	if (new_features)
	new_features = duplicate_feature_vector (new_features);
	}

	vec_add2 (new_features, f, 1);
	f->feature_index = feature_index;
	f->node_index = node_index;

	n_feature_config_u32s =
	round_pow2 (n_feature_config_bytes,
	sizeof (f->feature_config[0])) /
	sizeof (f->feature_config[0]);
	vec_add (f->feature_config, feature_config, n_feature_config_u32s);

	/* Sort (prioritize) features. */
	if (vec_len (new_features) > 1)
	vec_sort_with_function (new_features, feature_cmp);

	if (old)
	remove_reference (cm, old);

	new = find_config_with_features (vm, cm, new_features);
	new->reference_count += 1;

	/*
	* User gets pointer to config string first element
	* (which defines the pool index
	* this config string comes from).
	*/
	vec_validate (cm->config_pool_index_by_user_index,
	new->config_string_heap_index + 1);
	cm->config_pool_index_by_user_index[new->config_string_heap_index + 1]
	= new - cm->config_pool;
	return new->config_string_heap_index + 1;
	}

	u32
	vnet_config_del_feature (vlib_main_t * vm,
	vnet_config_main_t * cm,
	u32 config_string_heap_index,
	u32 feature_index,
	void *feature_config, u32 n_feature_config_bytes)
	{
	vnet_config_t old, new;
	vnet_config_feature_t new_features, f;
	u32 n_feature_config_u32s;

	{
	u32 *p = vnet_get_config_heap (cm, config_string_heap_index);

	old = pool_elt_at_index (cm->config_pool, p[-1]);
	}

	n_feature_config_u32s =
	round_pow2 (n_feature_config_bytes,
	sizeof (f->feature_config[0])) /
	sizeof (f->feature_config[0]);

	/* Find feature with same index and opaque data. */
	vec_foreach (f, old->features)
	{
	if (f->feature_index == feature_index
	&& vec_len (f->feature_config) == n_feature_config_u32s
	&& (n_feature_config_u32s == 0
	\|\| !memcmp (f->feature_config, feature_config,
	n_feature_config_bytes)))
	break;
	}

	/* Feature not found. */
	if (f >= vec_end (old->features))
	return ~0;

	new_features = duplicate_feature_vector (old->features);
	f = new_features + (f - old->features);
	vnet_config_feature_free (f);
	vec_delete (new_features, 1, f - new_features);

	/* must remove old from config_pool now as it may be expanded and change
	memory location if the following function find_config_with_features()
	adds a new config because none of existing config's has matching features
	and so can be reused */
	remove_reference (cm, old);
	new = find_config_with_features (vm, cm, new_features);
	new->reference_count += 1;

	vec_validate (cm->config_pool_index_by_user_index,
	new->config_string_heap_index + 1);
	cm->config_pool_index_by_user_index[new->config_string_heap_index + 1]
	= new - cm->config_pool;
	return new->config_string_heap_index + 1;
	}

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/